@TopCat416: Please try pressing the Volume Down and Power/Side buttons together for around 10 seconds until the phone restarts. Don't worry, this won't affect your personal data or settings. Now, head to the Galaxy Store > Tap the 3 lines in the bottom right > Updates, and check for any available updates for Samsung Health. If the issue persists, head to Settings > Apps > Samsung Health > Force Stop > Storage > Clear Cache, then try opening the app again. Let me know how you get on.
Download the Phone Info Sam app from Play Store and check if the Knox is 0x0. If it's 0x1, you need to unroot first then change motherboard. Unroot won't cost anything, but motherboard yes. Knox is hardware and software-based. My A51 (A515F/DSN SER Russia) has Knox status 0x0, which means it's functional.
